Scrubber head for floor cleaner

ABSTRACT

A mobile floor scrubber includes an orbital scrub head attached to a forward portion of its chassis. The scrubber head includes a rotary motor, an eccentric drive assembly and a floor engaging scrubbing pad which engages and cleans the floor. The eccentric drive mechanism introduces vibration in the orbital scrub head which is transferred to the chassis which reduces the energy used to perform the scrubbing task and reduces the operating efficiency of the floor scrubber. The floor scrubber further includes a cleaning fluid delivery system for providing a cleaning fluid to the scrubbing pad for application to the floor during the cleaning operation. The scrub head includes a first upper plate and a second lower plate arranged in vertically spaced relation, with both plates being generally planar and rectangular in shape. Disposed between and coupled to the upper and lower plates are plural spaced vibration isolators to reduce the transmission of vibration from the lower plate produced by action of the eccentric drive assembly to the upper plate and to isolate the floor scrubber&#39;s chassis from this vibration. Any vibration produced in the scrub head is further prevented from transmission into the scrubber&#39;s chassis by mounting the scrub head in closely spaced relation relative to the motor&#39;s rotary axis.

FIELD OF THE INVENTION

This invention relates generally to mobile floor cleaners having a scrubber head with a pad for engaging and cleaning the floor while undergoing eccentric movement without completely spinning

BACKGROUND OF THE INVENTION

Self-propelled mobile floor cleaners typically incorporate a scrubber head having a pad which engages and cleans the floor while transiting the floor. The scrubber head is typically attached to a forward portion of the chassis of the floor cleaner and operates in combination with a liquid floor cleaner delivery system to apply a cleaning solution to the floor while the pad engages and removes debris and dirt from the floor. The orbital motion of the cleaning pad is typically provided by an eccentric drive arrangement which includes a rotary motor and an off-axis drive arrangement which imparts an orbital motion to the scrubbing pad.

The typical orbital scrub head includes three generally flat, rectangular plates arranged in a spaced manner from one another. An upper plate is attached to the floor cleaner's chassis and is further coupled to an intermediate plate which, in turn, is connected to a lower bottom plate to which the scrubbing pad is attached. The top plate is attached to the intermediate plate by a first set of threaded couplers, while the intermediate plate is coupled to the bottom plate by means of a second set of threaded couplers. Each of these threaded couplers is inserted through a respective vibration isolator, with each threaded coupler maintaining its associated vibration isolator in position. The rotary motor drives the bottom plate to which the scrubbing pad is attached, while the intermediate plate remains in fixed position relative to the motor. This drive arrangement produces vibration between the orbitally displaced bottom plate and the top and intermediate plates. The rotary motor typically operates at a speed greater than 2000 RPM which places great stress on the components in the orbital scrub head. Current scrub heads typically incorporate a first set of vibration isolators disposed between the top plate and the intermediate plate, and a second set of vibration isolators disposed between the intermediate and bottom plates. These vibration isolators are designed and positioned so as to absorb vibration produced by the moving bottom plate. The top, or upper, set of vibration isolators are exposed to greater shear forces and vibration levels than the bottom, or lower, set of vibration isolators, and thus require more frequent replacement than the bottom set of vibration isolators. The top vibration isolators are also exposed to axial loads when the head is in a transport/storage position. This is an additional stress that contributes to premature top isolator failure. Shear force is also applied to the top set of vibration isolators when the scrub head engages a stationary object such as a wall or other vertical structure during operation. The present invention eliminates the aforementioned top plate and top vibration isolators, while maintaining acceptable floor scrubber chassis isolation from the high vibration levels produced in the orbital scrub head for increasing floor scrubber reliability, and extending floor scrubber operating lifetime and maintenance intervals.

OBJECTS AND SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to reduce the vibration transmitted from the scrub head of a floor cleaner to its chassis for improved floor cleaning operation, reliability and longevity.

It is another object of the present invention is to reduce the complexity and cost of a mobile floor scrubber by reducing the number of parts in the scrubber.

It is another object of the present invention is to increase the reliability and operating lifetime of a mobile floor scrubber.

A further object of the present invention is to direct more energy produced in the form of high levels of vibration in the scrub head of a mobile floor cleaner to the scrub head's floor engaging pad and less energy to the floor cleaner's chassis.

The present invention is directed to a scrub head for use in a mobile floor scrubber, the scrub head comprising: a rotary motor coupled to an eccentric drive assembly for providing high speed orbital motion; a fixed mounting plate having plural connectors for coupling to the mobile floor scrubber and an aperture adapted to receive and provide support for said rotary motor and eccentric drive assembly combination; a lower oscillating plate coupled to the upper mounting plate and having a floor scrubbing pad attached to a lower portion thereof for engaging and cleaning a floor, wherein the lower oscillating plate is further coupled to the motor and the eccentric drive assembly for undergoing orbital motion in displacing the floor scrubbing pad, and wherein the lower oscillating plate is subject to vibration during operation when displaced by the motor and eccentric drive assembly; and plural vibration isolators disposed between and coupled to the upper mounting plate and the lower oscillating plate for reducing the vibration transmitted from the lower oscillation plate to the upper mounting plate and to the floor scrubber.

BRIEF DESCRIPTION OF THE DRAWINGS

The appended claims set forth those novel features which characterize the invention. However, the invention itself, as well as further objects and advantages thereof, will best be understood by reference of the following detailed description of a preferred embodiment taken in conjunction with the accompanying drawings, where like reference characters identify like elements throughout the various figures, in which:

FIG. 1 is an upper perspective view of a conventional orbital scrub head as employed in the prior art;

FIG. 2 is a partially cut away upper perspective view of the conventional orbital scrub head illustrated in FIG. 1;

FIG. 3 is a vertical sectional view of the conventional orbital scrub head illustrated in FIGS. 1 and 2;

FIG. 4 is a perspective view of a conventional eccentric drive assembly as used in the prior art orbital scrub head illustrated in FIGS. 1-3;

FIG. 5 is an upper perspective view of an orbital scrub head in accordance with the principles of the present invention; and

FIG. 6 is a vertical sectional view of the inventive orbital scrub head illustrated in FIG. 5.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 1, there is shown an upper perspective view of a prior art conventional orbital scrub head 10 for use in a mobile floor cleaner. Scrub head 10 includes a rotary motor 12 attached to a top plate, or machine mount, 14 for attaching the scrub head to the chassis of the floor cleaner (not shown). Top plate 14 is attached to a mid plate, or motor mounting plate, 18 by means of plural threaded couplers, each inserted through a respective vibration isolator for maintaining the vibration isolators in position between adjacent plates. Two of these threaded couplers are identified with element numbers 19 a and 19 b in FIG. 1. The motor mounting plate 18 maintains the motor 12 in a fixed position within the scrub head 10. Attached to an upper surface of the mid plate 18 are a pair of coupling brackets 21 a and 21 b for attaching orbital scrub head 10 via linkage (not shown for simplicity) to the chassis of the floor cleaner. Mid plate 18 is coupled to a bottom plate, or oscillation plate, 32 by means of second plural threaded couplers where two of these threaded coupler/isolator combinations are identified in FIG. 1 as elements 23 a and 23 b. Attached to a lower surface of the bottom plate 32 is the combination of a backer plate 22 and a scrubbing pad 24. A solution delivery manifold 20 is attached to the orbital scrub head 10 for providing cleaning solution to the scrubbing pad 24 for cleaning a floor. An eccentric drive assembly 16 is not shown in FIG. 1, but its location in the orbital scrub head 10 is identified by the arrow in the figure to a position below and inline with the rotary motor 12.

Referring to FIG. 2, there is shown a partially cutaway upper perspective view of the orbital scrub head 10 illustrating the location of plural vibration isolators within the scrub head. For example, first and second top, or upper, vibration isolators 26 a and 26 b are shown in FIG. 2 as disposed between and coupled to top plate 14 and mid plate 18. There are two additional upper vibration isolators included in the orbital scrub head 10 disposed between and coupled to the top plate 14 and mid plate 18, but they are not shown in FIG. 2 for simplicity. Upper vibration isolators 26 a and 26 b are also shown in the vertical sectional view of the orbital scrub head 10 shown in FIG. 3. Disposed between and coupled to the mid plate 18 and bottom plate 32 are second plural vibration isolators, where two of these vibration isolators are shown in FIGS. 2 and 3 as elements 28 a and 28 b. As in the case of the upper vibration isolators, there are also four lower vibration isolators disposed between and coupled to the mid plate 18 and bottom plate 32, where the upper end portion of the two remaining threaded couplers each having an associated lower vibration isolator are identified in FIG. 2 as elements 21 a and 21 b. The lower vibration isolators 28 a-28 d absorb vibration energy generated by the movement of the bottom plate 32 by the rotary motor 12 so as to reduce the vibration level transmitted to mid plate 18 and prevent rotation of the bottom plate. Similarly, the upper vibration absorbers 28 a-28 d absorb some of the residual vibration energy provided to the mid plate 18 so as to further reduce the vibration energy level provided to the top plate 14 to limit the level of vibration provided to the chassis of the floor cleaner.

There is also shown in FIG. 3 a sectional view of the eccentric drive assembly 36 coupling the driveshaft of the rotary motor 12 to the orbitally displaced bottom plate 32 and backer pad 22 and scrubbing pad 24 coupled thereto. An exploded perspective view of the eccentric drive assembly 36 is shown in the right hand portion of FIG. 3, and an upper perspective view of the assembled electric drive assembly is shown in FIG. 4. The eccentric drive assembly 36 includes an upper offset mass member 40 which offsets the mass of the bottom plate 32 and backer plate and scrubbing pad combination during operation of the scrubber head. Offset mass member 40 is coupled to an eccentric member 42 by means of threaded couplers 44. The eccentric member 42 includes a generally circular aperture offset from its center which is adapted to receive the rotating driveshaft of motor 62 for providing eccentric motion in driving the bottom plate 32. Attached to a lower portion of a combination of the offset mass member 40 and eccentric member 42 is the combination of a bearing/mounting ring 46, a bearing 48, a washer/coupler 52 and a bearing mount 54. These components are coupled together and maintained in position by means of a second set of threaded couplers 50 and a third threaded coupler 56 to provide the assembled eccentric drive assembly 36 as shown in FIG. 4. The eccentric drive assembly 36 shown in FIGS. 3 and 4 is conventional in design and operation.

Referring to FIG. 5, there is shown an upper perspective view of the orbital scrub head 60 of the present invention. A vertical sectional view of the inventive scrub head 60 is shown in FIG. 6. Scrub head 60 includes a rotary motor 62 coupled to a motor mount plate 64. Motor mount plate 64 is coupled, and disposed in spaced relation, to a parallel bottom plate 66 by means of plural threaded couplers each engaging an associated vibration isolator, where the four vibration isolators are identified as elements 74 a-74 d in FIG. 5. As in the prior art approach shown in FIGS. 1-3, the inventive orbital scrub head 60 includes the combination of a backer plate 70 and scrubbing pad 72 coupled to a lower surface of the bottom plate 66. Similarly, orbital scrub head 60 includes a solution delivery manifold 68 for providing a cleaning solution to the scrubbing pad 72 during operation in cleaning a floor. Also as in the prior art, the orbital scrub head 60 includes a pair of rollers 82 a and 82 b disposed in respective forward corner portions of the orbital scrub head for accommodating contact of the orbital scrub head with vertical obstructions such as walls and structural support members during operation in cleaning a floor. The inventive orbital scrub head 60 further includes a conventional eccentric drive assembly 80 as illustrated in FIGS. 3 and 4 for orbitally displacing the bottom plate 66 and the combination of backer plate 70 and scrubbing pad 72 attached thereto.

Disposed on, or attached to, the upper surface of motor mount plate 64 are first and second chassis mounting couplers 76 a and 76 b, each of which includes a respective aperture 78 a and 78 b, for attaching the orbital scrub head 60 to the floor scrubber's chassis by means of appropriate linkage which is not shown in FIGS. 5 and 6 for simplicity. The spacing represented by the distance “X” shown in FIG. 6 positions the pair of chassis mounting couplers 76 a and 76 b in close proximity to the rotary motor 62 so as to reduce the level of vibration transferred from the orbitally displaced bottom plate 66 to the floor scrubber's chassis which is connected to the orbital scrub head by means of the first and second chassis mounting couplers 76 a and 76 b. The close spacing between the rotary axis of the drive motor 62, which is represented in FIG. 6 by the vertical dashed line designated Y-Y′, and the coupling points of the scrub head 60 to the floor scrubber's chassis provide an acceptable level of vibration transfer to the chassis. In addition, in the present invention each of the vibration isolators 74 a-74 d may be provided with a softer, or reduced, durometer value for accommodating the reduced vibration involved in the coupling between the orbital scrub head 60 and the floor cleaner's chassis. With a softer durometer value, the vibration isolators 74 a-74 d require less force, i.e., less energy to flex in the orbiting path of the bottom plate 60 so as to increase the operating life time of the oscillators before replacement, and to provide improved performance in the floor cleaning operation by directing more energy to the floor scrubbing task, while directing reduced energy in the form of vibration to the floor cleaner's chassis.

While particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the invention in its broader aspects. Therefore, the aim in the appended claims is to cover all such changes and modifications that fall within the true spirit and scope of the invention. The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only and not as a limitation. The actual scope of the invention is intended to be defined in the claims when viewed in their proper prospective based on the prior art. 

What is claimed is:
 1. For use in a mobile floor scrubber, a scrub head comprising: a rotary motor coupled to an eccentric drive assembly for providing high speed orbital motion; a fixed mounting plate having plural connectors for coupling to the mobile floor scrubber and an aperture adapted to receive and provide support for said rotary motor and eccentric drive assembly combination; a lower oscillating plate coupled to said upper mounting plate and having a floor scrubbing pad attached to a lower portion thereof for engaging and cleaning a floor, wherein said lower oscillating plate is further coupled to said motor and said eccentric drive assembly for undergoing orbital motion in displacing said floor scrubbing pad, and wherein said lower oscillating plate is subject to vibration during operation when displaced by said motor and eccentric drive assembly; and plural vibration isolators disposed between and coupled to said upper mounting plate and said lower oscillating plate for reducing the vibration transmitted from said lower oscillation plate to said upper mounting plate and to the floor scrubber. 